Conductive bridging memory device

1. A Conductive Bridge Random Access Memory (CBRAM) device comprising: an insulating electrolyte element sandwiched between a cation supply metal electrode and a bottom electrode, wherein the conductivity σ of the cation provided by the cation supply electrode in the electrolyte element increases towards the bottom electrode, wherein the electrolyte element comprises a top layer of a first dielectric material stacked on a bottom layer of a second dielectric material, wherein the cation conductivity σ in the first dielectric material is lower than the cation conductivity σ the second dielectric material, wherein the cation supply electrode comprises Cu or Ag, wherein the bottom electrode comprises tungsten, and wherein the second dielectric material is a thermally grown tungsten oxide.

2. The CBRAM device of claim 1 , wherein the second dielectric material comprises a chalcogenide.

3. The CBRAM device of claim 1 , wherein: the first dielectric material is an Alumina-oxide.

4. The CBRAM device of claim 1 , wherein the cation supply electrode further comprises: a Tantalum or a Titanium-Tungsten liner in contact with the electrolyte element.

5. The CBRAM device of 1 , wherein the bottom electrode comprises tungsten and wherein the second dielectric material is crystalline tungsten oxide.

6. A method for manufacturing the CBRAM device according to claim 1 , the method comprising: forming the bottom electrode; forming the electrolyte element on the bottom electrode; and forming the cation supply electrode on the electrolyte element, wherein the conductivity σ of the cation provided by the cation supply electrode in the electrolyte element increases towards the bottom electrode.